DE1448191A1 - Process and device for testing chemical substances - Google Patents

Description

Patent attorney Dipl.-Ing. E. Eder. ■ -

Some 13, Elisabeths *. U -... 1 4 4 8 1 9 1

Note: Metrimpex Magyar Müszeripari

Munich, September 5, 1968 File 2492 he

Procedure and device for testing chemical substances

The invention relates to a method and a device for Testing of chemical substances, through which the composition of liquid chemical substances, or the amount a sought-after contained therein. Material quickly, precisely and in a manner that satisfies the sanitary requirements can be determined economically.

Numerous laboratory test methods are known in which the amount of any component of a composite chemical liquid is determined in such a way, that from the starting material to be tested a series of dilutions produced and the highest degree of dilution is determined at which the substance to be tested with any

8098 "10 / Oi U ^{/ 2}

14h8191

a visible reaction with another reagent, e.g. discoloration, Formation of a precipitate, etc..

From this highest degree of dilution, the amount of the substance sought, i.e. the concentration of the substance in question in the initial solution "is determined. This process is called titration is particularly used for the quantitative determination of substances of unknown composition for which a "Accurate" analytical measuring method is not yet available fortune stands. Such methods are used in numerous areas of the chemical industry, such as dye Industry,. in the food industry, isotope tests, biological tests, etc. The usual, with the help of prepared by pipetting Titration procedure carried out at dilutions quite awkward and unsuitable for mass tests and the pipetting of substances harmful to health can have harmful effects even with special care cause.

The disadvantageous properties of the known method also include the fact that some of the means used for the test, after the test has been completed not songs can be used. The one for measuring containing isotopic or infectious substances Liquids used are pipettes, epruvettes after completion of the test procedure a lengthy one

8098 10/0 1 U

and to submit to arduous purification process what that Process makes “the test themselves and also the racks used to carry the same "are very expensive and difficult to handle and take up a lot of space *

The present invention has created a method and a device with which such chemical Qt off tests 10-2.0 times faster than with the previously customary method with large. Accuracy and - also with harmful ones. Substances can be carried out safely. th devices can not "wesertlichere .äeinigungsvorgar-ge-immediately for further Früfungen used werdei :. .vu3erdem the Geiäte used for the investigation are cillig and claim both in storage and ^w: \ hrerd testing only a small space.

In its detail, the invention becomes one: in the context with the example shown in the drawing described.

Figures 1 and 2 are the section and a partial top view of the test plate containing the row of holes.

Figure 3 is the section of the drip tube.

8098 10/0 1 U ^{BAD OWGINAL}

Figures 4- and 5 show the method for introducing the to liquid to be tested into the diluent serving drop lifter with handle sticks in front or side view.

Figure 6 shows how to use the dropper tube.

Figure 7 is a schematic to illustrate the introduction of the substance to be tested in the solvent and the mixing process.

In the method according to the invention, the diluting liquid is poured into the blind holes provided with a conical bottom Measure 2 of the plate 1 made of transparent plastic. This dilution liquid takes at the bottom of the holes 2 place. The number of holes 2 in the Plate 1 can be any, but due to practical Er Experiences, it is advantageous if one in six rows each Provides 12 holes. Can go to an exam depending on the nature one or more rows of holes are used for the investigation will. For most examinations, however, the use of one or two rows of holes is sufficient, since they are twelve times larger or twenty-four-fold dilution of the titre already specifies the substance to be tested with sufficient accuracy. So can one can carry out six examinations simultaneously with a single plate 1.

To the. In the manufacture of the plate 1, a hydrophobic plastic is expediently used so that it

. BATH

Dear Ulsters.u.cUuiiß'-lightly marked; and after-

- 5 -
First examination can be used.

The measurement of the diluent is carried out with a dropper (Fig.3) · This is the essence after a funnel with a container part 3 made of plastic, in which an airtight closing attached dropper tube 4 and one, likewise In the container part fastened, made of plastic or glass tube extension 5 is provided. In the container part 3 or on the tubular extension 5 there is no line indicating the quantity. The drop by drop added amount of liquid is therefore due to the number of the lower end 6 of the Rorchen separating drops determined. The size of the amount of liquid contained in each drop becomes besides the specific gravity and the surface tension of the liquid from the outer diameter of the Tube 4- determined. During the time of the test there is generally a temperature in the room of 20 - 2 ° C, so that the effect of the temperature and the external atmospheric vapor pressure is neglected can be. The drip devices are for each diluent or The reagent has to be calibrated once, i.e. it has to be determined how large the volume of the with the drip device in question is the drop formed by the substance in question.

8 0 9 8 1 0/0114

The drip device shown in Fig. 3 is used in such a way that it is in the diluent or is immersed in the reagent solution, after which due of the law of communicating vessels ". the funnel 3 and even part of the tubular extension 5 fills with liquid. Now the top end will of the tube extension closed with the finger and the end of the tube 4- held over the opening 2 of the plate 1, then the upper opening of the tubular extension a little ventilated, so that a drop forms on the lower surface 6 of the tube 4- and tearing off from there in the corresponding hole 2 falls. ,.

Since the amount of substance of the individual drops is known, the desired amount of the diluent or reagent solution can be measured drop by drop » "" ■ ■■■■■■ "" ■ - - ■■ "^ ■ ■." "■ -

As soon as the necessary diluent is contained in the holes 2 used for testing, the 4 and 5, consisting of the two spirals 7 and 7a, brought into contact with the surface of the liquid to be tested. The outer surfaces of the spirals 7 and 7a are useful Hemispherical surfaces. · The threads of the spirals form narrow capillary gaps, the width of which is appropriately smaller than 0.5mm. The spirals 7 and 7a are combined that die.straight legs 8 and 8a of the

8 0 9810/01 ^14/7

Wire forming spirals is pressed into the bore 10 of the handle 9 which can be manufactured from light metal are; so spirals 7 and 7a together form a spherical surface .

By bringing the drop lifter into contact with the surface of the liquid to be tested, the Liquid penetrate through the gaps between the spiral flights into the interior of the drop lifter and remain there even after it has been lifted out of the liquid, since the liquid surface tension between the spiral flights is large enough is to prevent the liquid in the spiral ball from flowing out.

The iv.narity of this fluid is due to the internal The cap of the spiral ball is determined. The difference in the ikeniscus lines located between the spiral ducts is so small in the various liquids that the amount of liquid inside the spiral ball can be regarded as practically constant.

Obviously, in order to conduct a test, one must have a certain amount of the diluent in the holes the plate 1 and for this purpose of the to be tested Mix in a certain amount of substance. the

SAD OFHGfNAL

8 O 9 8 1 O / O 1 U

The amount of diluent can - as already described - be set precisely, easily and quickly with the dropper and the amount of the substance to be tested can be measured just as quickly and easily with the aid of the drop lifter shown in Fig. 4. The volume of the drop lifter consisting of the spirals 7 and 7a should accordingly be dimensioned in such a way that it is consistent with the volume of the drops formed with the drop device. The drop lifter can therefore be suitable for taking up 0.025, 0.05 and 0.1 ml of liquid, for this purpose drop devices are to be used which generate drops of liquid with a volume of 0.026 ml. The desired volume of the drop lifter can with a tolerance of - 2 % are adhered to. -

The liquid picked up with the drop lifter, i.e. the amount of solution to be tested, is poured into the first Hole 2 of the plate 1 made and with your finger around the longitudinal axis of its handle 9 rotated. As result this process is carried out with the drop lifter in the dilution liquid located at the bottom of the hole introduced solution to be tested with the diluent completely mixed. After removing the drop lifter, from the hole is located inside the same again a liquid, but compared to that the original liquid to be tested is already thinner, since half of the liquid is in the drop lifter

8 0 9 8 T 0/0 1 1 U. ·. BATH QWQINAL

Liquid already from the diluent of the first Loches comes from “This one, in relation to the earlier state Half the concentration of the solution is now introduced into the second hole 2 of the plate 1 and so continuously also in the next holes of the hole range. When the same drop lifter is inserted into all holes in the row of holes solutions of specific, successively decreasing concentrations are obtained in the individual holes .

The next step is to bring a reagent into the holes using the dropper shown in Fig. 3 the row of holes and determines the concentration of the solution to be tested by calculation in a known way, due to the number of holes in which reaction phenomena show up.

All rows of holes in plate 1 can be used simultaneously for the same or different investigations be used. The measurement of the diluents and the reagents is carried out separately, hole by hole. Mixing the substances to be tested with the However, the diluent can also be carried out at the same time, i.e. with one handle (Fig. 6), because the Shape of the handles. 9 the dropper enables to carry out the work of six drop lifters at the same time. This significantly reduces the test required length of time.

809810/0114 / 10

- ίο -

The drop lifter composed of hemispherical spirals is made of heat-resistant steel. the Drop lifters are burned down in flames after completion of the individual tests and thus completely disinfected. This is how the drop lifters are, even after testing for infectious substances, after they have burned off Can be used again for a few seconds.

The ancestry is explained in more detail by the following examples explained:

Example 1; Titration of dye solutions. The titration of each dye solution is carried out with the setting of two titration series. A drop, ie 0.025 ml, is measured from the dilution solution into the wells of the test plate using the drop device (Fig. J>). (Only the first well of the second row is an exception, in this two drops, "ie 0.05 ml of dilution liquid are introduced). Then a sample is taken from the dye solution to be tested with two drop siphons of 0.025 ml each and these are mixed in In the other wells, gradually diluting the dye with the drop lifters, a steadily decreasing color scale is obtained, in which the degree of dilution of the individual elements of the scale is known

80 98 10/0 1 U / 11

Dilution values of the first row are 1: 2, 1: 4, 1: 8 etc., those of the second row 1: 5, 1: 6, 1:12, etc. Then that dilution value is selected whose color corresponds to that measured in the third row Unit of measurement (e.g. 1 gamma / ml). This dilution value gives the concentration of the tested Dye in gamma / ml. If the color of the etalon falls between two dilution values, the actual Value can be determined by interpolation.

Example 2 : Measurement of the value of an antibiotic. In the pharmaceutical industry, it is often necessary in the production of antibiotics to be able to quickly control or determine the antibiotic content of the semi-finished products in the course of production. With the aid of the method, this determination is carried out in a ethyl red indicator containing: the nutrient liquid, prepared as a diluent according to the above example, series of dilutions. The suspension of a bacterium sensitive to the antibiotic is measured into each well and the plates are placed in a thermostat. In those samples in which the concentration of the antibiotic is so low that it no longer prevents the growth of bacteria, the color changes dee indicator by effect of CO formed by the breathing of the bacteria. on yellow. The concentration of the -a.ti-

BATH ORIGINAL

80 98 10/0 1 U /> -

biotikums is characterized by the dilution value at which the bacteria stop breathing, which circumstance is indicated by the red color of the indicator.

Example 3: In the food industry, based on the determination of the germ content of individual foods (such as milk, ice cream), the brewability or the fact whether the tested product is spoiled is determined. The germ count can also be determined with the dilution of the substance to be tested due to the principle used when titrating the antibiotic.

The advantages of the inventive method and Device are the following:

The person performing the test does not come into direct contact with the substance to be tested, the measurements necessary for testing the substance are based on the exclusion of subjective factors carried out on a purely objective basis, so that the test results compared to the results of the previously known Procedures are significantly more accurate; the time required for the individual tests is much shorter and therefore, the number of tests that can be performed by one person in the unit of time is greater. The low expenditure of time and the reliability of the method according to the invention also offer the possibility of carrying out

809810 / 01U

Mass tests in the laboratory.

The number and purchase price of the devices required for the tests is only a fraction of that the devices required for the previously known methods. In addition, in the method according to the invention, the Devices are not withdrawn from further work even after testing isotope-containing or infecting substances. The seam requirement required for the exams is small.

One of the greatest advantages of the inventive method is that it compares to this method to the amount of substance required for the known tests, only about a tenth of the same to achieve of even more precise test results are necessary. This enables many of these to be carried out Tests carried out with the previously known procedures - although for the work of industry and research laboratories this would have been necessary long ago - were not feasible.

* The invention is not limited to the embodiment of the

oo for example, specified devices are limited. So can

For example, instead of the drop lifters formed from spirals, spheres or cylinders made from platelets arranged with capillary gaps, disks or plate structures held together by spacer rings with capillary dimensions and the like are used. ^{on arn} ^ ^a _,

Dfpl.-ln g. E. Ede *

Claims (1)

Patent attorney n «, Elisabeths *. U Claims 1. Procedure for carrying out chemical tests with a series of gradual dilutions, characterized in that in the individual vessel-like formed wells (2) of a plate (1) by means of a drop device generating certain amounts of substance (5-5) certain amounts of a diluting liquid are introduced, then with the help of a, through capillary Forces a certain amount of liquid absorbing drop lifter (7-1o) the corresponding amount of to liquid to be examined introduced into the first vessel-like depression and with the one located there Dilution liquid is mixed, with one of the lifters lifted out of the recess introduced amount of liquid lifts out the same volume of the now diluted liquid, this then enters into the second well and mixed with the diluting liquid located there, and this process as long in most of the vessel-like wells repeats until the desired number of gradual dilutions is made, thereby making the carries out the desired reaction with these dilutions in a manner known per se. 2. Device for performing the method according to Claim 1, characterized by a plate (1) in wel- 809810 / 01U / 15 rather vessel-like - expediently arranged in rows wells (2) are formed, furthermore by a suitable for generating drops of constant size Dropper (5-5) and through one, by means of capillaries Forces suitable for taking up a certain amount of liquid drop lifters (7-10). 5. Device according to claim 2, characterized in that that the drip device from one, expediently made of plastic manufactured funnel-shaped container part O) an expediently made of stainless steel Drip tube (4) and one, an extension of the container forming ßohrfortsatz (5) consists. 4. Apparatus according to claim 2, characterized in that that the drop lifter consists of two Lietall spirals, which are designed in such a way that the spiral flights each form a hemispherical surface, which are next to each other arranged to form a full spherical surface, the spiral threads are arranged so tightly that the capillary forces the absorbed liquid in the one enclosed by the hemispherical spiral structure Can hold space. Patent attorney Ä '- Eder 809810 / on;